The One Arm Pushup is an advanced exercise that targets the upper body, particularly the chest, shoulders, and triceps. To perform this exercise, start in a standard pushup position with your feet slightly wider than shoulder-width apart for better balance. Place one hand on the ground directly under your shoulder and the other hand behind your back. Engage your core to maintain a straight line from your head to your heels. Lower your body by bending the elbow of the supporting arm, keeping your body straight and avoiding any twisting. Push back up to the starting position. This exercise requires significant strength and stability, so it is recommended for advanced practitioners.